In order to minimize pollutants such as NOX, internal combustion engines may include an exhaust gas recirculation (EGR) system that includes an EGR valve. EGR systems primarily recirculate exhaust gas by-products into the intake air supply of the internal combustion engine. The EGR valve can be used to redirect a portion of exhaust gases to an intake conduit, such as an intake manifold, so that the redirected exhaust gases will be recycled.
The exhaust gas which is reintroduced to the engine cylinder reduces the concentration of oxygen therein, which in turn lowers the maximum combustion temperature within the cylinder and slows the chemical reaction of the combustion process, decreasing the formation of nitrous oxides (NOx). Furthermore, the exhaust gases typically contain unburned hydrocarbons that are burned on reintroduction into the engine cylinder, further reducing the emission of exhaust gas byproducts that would be emitted as undesirable pollutants from the internal combustion engine.
In order to improve engine performance and reduce emissions of pollutants, it has been found to be advantageous to cool the exhaust gases that are being recirculated by the use of various devices, such as, for example, air-to-air coolers, water to air coolers, or other heat transfer devices. However, such devices require an increase in the overall heat rejection capability of the engine. For example, additional radiators and/or larger, more cumbersome radiators may be required in order to provide such an increased heat rejection capability, especially where the engine is used in a slow-moving vehicle or machine.
It is also known to use a device commonly known as a vortex tube or a Ranque-Hilsch tube in order to separate components of exhaust gases. For example, U.S. Pat. No. 3,566,610 discloses a method and apparatus for separating components of exhaust of an internal combustion engine by density using a vortex tube.
The present invention is directed to overcoming one or more of the problems or disadvantages associated with the prior art.